As subterranean fluid exploration becomes increasingly complex, the importance of analyzing seismic samples increases. Seismic imaging, or migration, is a process that focuses and positions seismic reflections at their true geological locations. Over the years, significant effort has gone into the search for fast and accurate imaging algorithms. See, e.g., Yilmaz, O. 2002, “Seismic data analysis: Processing, Inversion, and interpretation of seismic data”, Society of Exploration Geophysicists, Tulsa, Okla. and Claerbout, J. F., 1985, “Imaging the Earth's Interior”, Blackwell Scientific Publications, London. Among the various processing methods employed, prestack depth migration is one of the most time intensive to perform. Wave equation and Kirchhoff migration represent two typical groups of algorithms that are widely used within the oil and gas industry.
Target oriented prestack depth migration has also been used where only a small volume of output is produced, but it still takes days, if not weeks, to complete because all, or a significant portion of the input prestack seismic data needs to be migrated. Many wave equation depth migrations cannot be made target oriented, or at least not easily, because of the inherent global nature of the underlying method. Kirchhoff prestack depth migration can be target oriented on output, but all seismic traces within the aperture range must be migrated even though many of them will not contribute to the image in the target area at all.